Manner op constructing- coffee-mills



J. RIT TENHOUSE.

Patented Juiy 12; 1839.

UNITED STATES PATENT OFFICE.

JOHN RITTENHOUSE, OF PHILADELPHIA COUNTY, PENNSYLVANIA.

MANNER OF CONSTRUCTING COFFEE-MILLS.

Specification of Letters Patent No. 1,215, dated July 2, 1839.

b (1ZZ 107mm it may croncemz:

Be it known that I, JOHN RITTENHOUSE, OE the county of Philadelphia and State of Pennsylvania, have invented an Improvement in the Manner of Constructing a Mill for Grinding Cofi'ee; and I do hereby dec]are that the foilowing is a full and exact description thereof.

The kind of mil1 in which my impromn1ent is made is that in which a conicai, toothed nut is made to revolve in a corre sponding ho]low cone; and the object of my improvement is s0 to attach the stop upon which the iower end of the axis of the nut revolves to confine it more efiectually than 1ms hitherto been done, so as to prerent the teeth of the nut from being forced into contact with those of the hollow cone or shell, by the introduction of any hard substance in the miH aiong with the cofi'ee. In miHs of this description the fine teeth on the lower and of the nut are to revolve, as nearly as possible, in contact With those on the shell, or hoilow cone, and if the nui: is capable oi" yielding, even in a slight degree, bthe interposition of any hard substance between the. nut and the sheil, the teeth of the two are forced into contact, and their edges are consequently taken ofi". The sing1e cross bar which is ordinariiy employed as a step, and which is notched into the lower edge of the shell, although it pertorms its oflice snfiiciently well under ordinary circumstances, has been found to spring or yield, under a hard strain, sufiicient]y to admit of this injurious efi'ect, even when tightly screWed up, and to obviate this, I have adopted the plan represented in the accompanying drawing, which is a representation of the machine detached from the wooden box to which such mills are affixed.

A A is the outer sheil or hollow cone, and B B is the step through which passes the. center screw C to support and regulate the shaft of the revolving nut. This stop is made in the form of a cross, and it is notched at each of its ends so as to slip int0, or onto, the lower edge of the shell, thus afiording it a permanent bearing Will efiectually secure it from all motion, even When drawn but moderateiy tight by the screws D D. A similar efiect Will be produced by making the step with three arms, instead of in the form of a cross, giving it three bearing points upon the periphery of the shell; the step may also have but two arms, extending across, and in one piece With a ring fitting onto the lower edge of the shell, and having a groove, or rabbet, to aid in confining it in place. A fitting of this kind is very easiiy made as I construct both the shell and step of malleable cast iron.

Having thus fully described the nature of my improvement in the stepof a cofi'ee mill, What I claim as my invention, and desire to secure by Letters Patent, is

The forming such a step as that it shail have three, or more, distinct points of bearing, or bear upon the whole, or the larger portion, of the lower edge of the hollow cone, or shell, the bearings being so notched, or formed, as to check a11 lateral motion, in the manner herein set forth.

JOHN RITTENHOSE.

Vitnesses THOS. F. JONES, GEORGE VEST. 

